Electrical terminal plug



Jan. 31, 1939, J WERTZHBSER 2,145,701)

ELECTRICAL TERMINAL, PLUG Filed July 15, 1935 J B gg {if (2781' ATTORNEYS Patented Jan. 31, 1939 UNITED STATES ELECTRICAL TERMINAL PLUG Joseph Wertzheiser, Newark, N. J., assignor to Hatfield Wire & Cable 00., Hillside, N. J., a corporation of New Jersey Application July 15,

17 Claims.

An object of the present invention is to provide an electrical plug which combines the advantage in simplicity and security against breakage, characteristic of soft flexible rubber body plugs and the advantages in the fixed spacing of the terminal prongs characteristic of rigid body plugs, of vulcanite, Bakelite or the like.

Another object is to provide a skeleton electrical plug assembly which lends itself for incorporation in an insulating body of any of a wide variety of constructions, including a pre-molded soft, rubber body, a soft rubber body molded in situ thereabout, or a rigid body of vulcanite,

- Bakelite or the like assembled with the preassembled skeleton body enclosed therein.

Another object is to provide a plug of the above type which may be readily produced at low cost by simple methods and equipment, and admits of use of a premolded flexible rubber body, with the exertion of but little strain thereon in the course of assembly, so that a harder, less perishable, and less expensive flexible rubber may be used for the purpose than is required in constructions where considerable distortion is necessarily incured in the installation of the prongs and conductors.

Another object is to provide a construction of the above type, in which the danger of corrosion frequently concomitant with the use of solder connections is completely eliminated and in which the security of electrical contact between the parts is thoroughly dependable.

A feature of the invention is the skeleton plug body, preferably comprising a fiat, rigid, insulating carrier core to which the terminal prongs and the corresponding exposed ends of the electrical terminal cord are rigidly assembled. The carrier core may be a fiber plate to the ends of which the respective terminal prongs are assembled in electrical contact with the corresponding conducto'r terminals. Preferably the carrier core plate has lateral lugs, the terminal prongs having apertures embracing said lugs and contacting the exposed conductor ends which are passed through apertures in the core plate and lapped over the lugs.

The conductor cord in the application to premolded soft rubber plugs is passed through the usual longitudinal port in the latter, the assembly of the carrier and prongs is then established, whereupon the prongs and carrier core are depressedinto corresponding cavities in the plug body, with the free ends of the prongs protruding from the face and the conductor cord protruding from the neck of the body. Preferably 1935. Serial No. 31,356

the face opening of the rubber plug body snugly engages the prongs and the edge of the carrier core, the lugs of which extend into corresponding bays in the body of the plug.

In the accompanying drawing, in which is shown one of various possible embodiments of the several features of the invention,

Fig. 1 is a perspective view of a preferred form of plug in assembled condition.

Fig. 2 is a view of the plug in. longitudinal cross-section, showing the assembly of the carrier core to the conductors.

Fig. 3 is a view similar to Fig. 2 showing the next step in the assembly, including the application of the terminal prongs,

, Fig. 4 is a view similar to Figs. 2 and 3 showing the first stage in the introduction of the skeleton plug into the rubber body.

Fig. 5 is a view of the completed assembly in longitudinal cross-section taken on the line 5'-5 of Fig. 1,

Fig. 6 is a view in longitudinal section taken on line 6-6 of Fig. 5, but with-the prongs broken off,

Fig. 7 is a transverse sectional view taken on line of Fig. 5,

Fig. 8 is a detail, viewed from line 8-8 of Fig. 2,

Fig. 9 is a detail sectional view taken on line 99 of Fig. 3, showing the first step in the assembly of the terminal prong to the carrier core.

Fig. 10 is a transverse sectional view taken on the line lil--I0 of Fig. 3 showing the complete assembly of the prong on the carrier core, and

Fig. 11 is a perspective view of the carrier core.

Referring now to the drawing, there is shown an electrical connector plug including an insulating body 20 with prongs 2| and 22 protruding outwardly from the face 23 thereof, and a flexible electrical cord 2t protruding from the neck 25 thereof. While the drawing shows a flat body of width much greater than its thickness and while such construction is preferred, it will be understood that the invention is also applicable to constructions of more conventional shape.

Referring now to the cross-sectional views, the invention in its preferred embodiment comprises a piece 26, preferably in the form of a thin plate of insulating rigid fiber which serves as a' carrier core for mounting both the prongs 2| and 22 and the inner ends of the electrical terminal cord 24, with the unsheathed extremities of the latter electrically connected to the respective prongs into a rigid skelton terminal plug.

In a preferred embodiment, the carrier core has apertures 21 and 28 therethrough, through which lar apertures 33 near their the corresponding unsheathed stranded extremities 29 of the conductors are first extended to pass over the corresponding edges of the carrier core, the terminal prongs being then rigidly clamped to said core in secure electrical and mechanical connection with the conductors.

In the construction shown and preferred, the carrier core has lateral lugs 30 and 3| of reduced width, the outermost edges of which are centrally notched at 32 for accommodating the conductor ends. 29 which are folded over the lug.

The terminal prongs have generally rectanguroots so that the lugs 30 and 3| 34 to accommodate the conductor portions 29. The lengths of the prongs 2| and 22 are accurately positioned and located by the shoulders 35 flanking the lugs 30 and 3| on the carrier core 26..

The prongs are now pressed inward as best shown at 39 in Fig. 10 by resort to an appropriate machine tool to cause the bowed portion rigidly to grip the conductor ends 29 and firmly to secure the respective prongs and conductor terminal ends in tight mechanical engagement with the carrier core, and for secure electrical connection between the prongs and their associated conductors.

Preferably the apertures 21 and 28 in the carrier core 26 are not circular but generally trapezoidal in form with their wider bases 36 innermost and their narrower preferably rounded bases 31 outermost and near the respective roots of the respective lugs 30 and 3|. By this arrangement it is clear, that where the usual stranded conductor terminal cord is employed the ready insertion of the multiplicity of separate strand ends 29 into the aperture 21 or 28 is expedited and the compacting of said strands is facilitated as the latter are drawn against the narrower base 3| preparatory to lapping over the notch 32.

The skeleton assembly thus far described of carrier core, prongs and conductor cord may be molded into any kind of suitable insulating plug body structure, such for instance as the molded rubber body of the Frantz patent, No. 1,611,014 of December 14th, 1926. Alternatively there may be molded or assembled about said skeleton assembly a non-flexible, rigid body of hard vulcanite, Bakelite, glass, ceramic or the like. In the drawing I have shown another alternative, that is, a pre-molded flexible solid insulating body 20 for the-skeleton plug described, and this preferably, made of soft rubber composition. The insulating body 20 serves chiefly for electrical protection and convenience of handling, and need in no sense be depended on for mechanical security or rigidity the prongs and the conductor cord.

The insulating body 20 as shown in the-drawing may be of the external appearance shown in Fig. 1 and above described, with a longitudinal port 38 therethrough for housing the terminal cord 24, which latter is first inserted therethrough as suggested in Figs. 2 and 3, prior to assembly thereto of the carrier core 26 and the terminal prongs 2| and 22, as previously described.

The insulating body is hollowed out to accom modate the carrier core and associated parts. Forthis purpose the rubber body has a narrow, deep cavity 40 in the axial plane thereof corresponding in depth, width and thickness to the corresponding proportions of the carrier core 26 as shown. The ends of said narrow cavity have correspondingly narrow bays 4| and 42 of dimay be readily passedtherethrough, said apertures being slightly bowed laterally at of' connection or spacing of mensions corresponding to those of the respec-- tive lugs 30 and 3| for accommodating the latter. The narrow ledges 43 and 44 at the face of the body extend over said bays. The cavity in the plug also has longitudinal portions laterally and transversely of the narrow cavity 40, as at 45 and 46 for accommodating the respective roots of the prongs 2| and 22 which bottom in corresponding wells 41 in the body. Preferably the face of the insulating body is normally closed, except for the ports 45 and 46' for the corresponding prongs 2| and 22.. Lips 48 and 49 in the face of the body closed at longitudinal slit connecting the middles of ports 45' and 45' preferably shield the entrance to-the narrow cavity 40 for the carrier core, although if desired, these lips may be dispensed with.

It will be apparent that after the assembly has been completed to the stage shown in Fig. 3,

the skeleton plug need merely be pressed inward, in which application, as shown in Fig. 4, the lugs 30 and 3| spread the ledges 43 and 44 outwardly as shown. As the skeleton plug is pushed home to the position shown in Figs. 5 and 6, the roots of the prongs 2| and 22 become lodged in the corresponding wells 41 in the body, the carrier core becomeslodged in its cavity 40, the lugs 30 and 3| on said core enter and fill the respective bays 4| and 42, the ledges 43 and 44 snap over the outer edges of said lugs and the lips 48 and 49 close over the otherwise exposed outer edge of the carrier core 26. In the complete assembly, the forward ends of the prongs 2| and 22 alone protrudefrom the face 23 of the plug, and the conductor cord 24 protrudes from the neck 25 of the plug body. Asshown in Fig. 5, the skeleton plug is enclosed and so securely fixed within the rubber body that it could not be removed by hand, for the carrier core is blocked against possible withdrawal through the neck of the body, and the face thereof must be stretched along the plane of said core to permit disassembly and this can be done only by resort to appropriate tools.

The first step of inserting the conductor cord through the body imposes no strain whatsoever upon the latter, and the insertion of the assembled skeleton plug deflects only the outer and wider part of the face of the plug as shown in Fig. 4. to a moderate degree, largely at the region of the ends of the thin carrier core 26. The resiliency at the relatively expansive area of the face 23 effectively snaps the ledges 43 and 44 to unstressed position over lugs 30 and 3| as the carrier core installation reaches-home location. The presence of this core piece with the short prongs carried thereby and the mode of installation thereof in the rubber body assures a secure and reliable assembly, even with the use of relatively flexible rubber for the body, which flexible rubber is less perishable than the harder rubber with a greater proportion of filler generally required in conventional flexible rubber terminal plugs.

The rubber body, though it performs essentially the function of insulating and of housing the skeleton terminal plug structure, is itself considerably strengthened by the rigid carrier core 26 extending as a reinforcement across the width of the body, and is further strengthened across its thickness by the terminal prongs 2| and 22. The terminal prongs and carrier core determine as shown, an I-beam reinforce core for the rubber body, which is therefore not subject, even under severe conditions of handling. to

developing minute cracks inimical to the usefulness of the device.

It will thus be seen that there is herein described an article in which the several features of this invention are embodied, and which article in its action attains the various objects of the invention and is well suited to meet the requirements of practical use.

As many changes could be made in the above construction, and many apparently widely dif ferent embodiments of this invention could be made without departing from the scope therc of, it is intended that all matter contained in the above description or shown in the accompanying drawing shall beinterpreted as illustrative and not in a limiting sense.

Having thus described my invention, wnat I claim as new and desire to secure by Letters Patent is:

1. An electrical terminal plug comprising a solid flat insulating core piece, insulated flexible conductors and conducting terminal prongs with slots near their ends fitted over said core piece with the bare extremities of said conductors mechanically held by said fitted portion for electrical connection with the respective prongs, a solid resilient insulating body having a face and a neck, said core piece being lodged. in a corresponding cavity in the axial plane of said body, with the prongs protruding from the face thereof and the insulated conductors from the neck thereof. I

2. An electrical terminal plug comprising a rigid, fiat insulating carrier core piece, an insulated flexible conductor cord having unsheathed ends in contact with said core piece, conducting terminal prongs with slots, the walls of which em brace a part of said core piece and tightly retain said conductor ends on saidcore piece in a rigid assembly therewith. and asolid flexible insulating body having a face and a neck and having a cavity in an axial plane thereof, lodging and resiliently gripping said core piece, with the ends of the prongs protruding from the face and with the insulated conductor cord protruding from the neck of said body.

3.- An electrical terminal plug comprising a rigid, flat insulating core piece, an insulated flexible conductor cord having unsheathed ends in contact with said core piece, conducting terminal prongs with slots, the walls of which tightly grip said conductor ends against said core piece in a rigid assembly therewith, and a solid fiexible insulating body having a face and a neck and having a cavity in an axial plane thereof, lodging said core piece with the ends of the prongs protruding from'the face andwith the insulated conductor cordprotruding from the neck of said body, the face of said body presenting lips extending .the entire otherwise exposed edge of said core piece and resiliently closing thereby to conceal the same from view.

4. An electrical terminal plug comprising a rigid, fiat insulating core piece, an insulated fiexible conductor cord having unsheathed ends in contact with said core piece, conducting terminal prongs with slots, the walls of which tightly grip said conductor ends and securely held on said core piece in a rigid assembly therewith, and a solid flexible insulating body having a cavity in an axial plane thereof, lodging said core piecev with the ends of the prongs protruding from the face and with the insulated conductor cord protruding from the neck of said body,,the face of said body presenting ledges resiliently closing over the ends of said core piece, the face further presenting lips lengthwise of the core piece to overlap the otherwise exposed edge thereof.

5. In an electrical terminal plug, a rigid insulating carrier core piece having lateral lugs, a conductor cord having unsheathed ends engaging said lugs, and terminal prongs firmly gripping said conductors for electrical contact therewitlri said prongs having slot means for secure mechanical mounting thereof upon said carrier core piece. 6. In an electrical terminal plug, a flat, rigid insulating, generally rectangular, fibre carrier core having reduced lateral lugs, and apertures adjacent. said lugs, an insulated conductor cord having unsheathed ends through the respective apertures and about the respective lugs, and conducting terminal prongs longitudinally slotted to embrace the respective lugs and their associated conductor ends for electrical engagement therewith and for mechanical mount upon the carrier core.

7. In an electrical terminal plug, a fiat, rigid insulating, generally rectangular, fibre carrier core plate, having reduced lateral lugs, and apertures adjacent said lugs, an insulated conductor'cord having unsheathed ends through the respective apertures and about the respective lugs,

and flat conducting prongs longitudinally slotted near one end thereof and embracing the respective lugs, with their respective widths extending at right angles'to the plane of the carrier core contact with the conductors and secure mechanical mount upon the. carrier core plate.

8. In an electrical terminal plug, a flat,'rigid, generally rectangular carrier core plate having reduced lateral lugs and defining shoulders flanka ing said lugs, a conductor cord having unsheathed ends engaging said lugs, terminal prongs having openings therein passed over said lugs and snugly engaging the conductor ends, said shoulders serving as stop members to position the respective prongs in parallel relation-with their widths at right angles. to the plane of the core .plate.

9. An electrical terminal plug comprising a rigid carrier core plate of insulating fiber'having a pair of apertures therethroughnear the lateral edges thereof, said apertures being wider at theirinner ends and narrower at their outer ends for facility of insertion therethrough of the stranded exposed ends of a conductor cord, terminal prongs having slots, the walls or which tightly embrace the ends of said fiber plate in electrical contact with the respective conductor ends, and an insulating body enclosing the fiber plate with the conductor prongs protruding from one end thereof and the conductor cord from the other end thereof.

10. An electrical terminal plug'comprising the combination of a rigid insulating fiber carrier core having reduced lateral lugs and having apertures therethrough adjacent said lugs, each of said apertures generally trapezoidal in shape with the wider bases innermost and the narrower bases adjacent the respective lugs, an electrical conductor cord having exposed ends which pass respective lugs and clenched for attachment to said carrier core and in electrical contact with closing the carrier core and its lugs and having ports at its face for protrusion of the prongs,

the conductor ends, and an insulating body 'enand a port opposite its face through which protrudes said conductor cord.

11. An electrical terminal plug comprising an insulating flexible rubber body having a face and a longitudinal port from the opposite end thereof, a narrow, deep transverse cavity therein adjacent said face, said plug having bays at the ends of said cavity, a rigid flat insulating carrier corehaving reduced lateral lugs, a conductor cord having exposed terminals at said lugs and conducting terminal prongs having slots, the walls of which tightly embrace said lugs and in electrical contact with said conductor terminals, said carrier core being lodged in said cavity with the lateral lugs thereof lodged in said bays and resiliently gripped by the body and with the terminal prongs protruding from the face of and the conductor cord through the longitudinal port in the body.

12. An electrical terminal plug comprising a flexible solid'insulating body having incorporated therein a thin rigid insulating carrier core extending in a longitudinal plane thereof, terminal prongs having slots, the walls of which tightly embrace said carrier core and protruding from the face of said body and a conductor cord protruding from the neck of said body and having its extremities rigidly connected in electrical engagement between the carrier core and the respective prongs.

13. An electrical terminal plug comprising a soft rubber insulating body having a face and a neck and generally rectangular in cross section and of width considerably greater than its thickness, a thin rigid insulating carrier core extending across the width and in the axial plane of said body and within the interior thereof, electrical terminal prongs having slots, the walls of which tightly embrace the ends of the carrier core and protruding from the face of said insulating b'ody,'an'd an insulated electrical terminal cord protruding through the neck of said body and having its extremities rigidly affixed in electrical engagement with respect to the respective I terminal prongs.

14.An electrical terminal plug comprising a flexible premolded insulating body having a face and aneck, said body being generally rectangular in cross-section with its thickness materially less than its width, a skeleton electric plug gripped within a corresponding cavity in said body, said skeleton plug being rigid and I-beam shaped in cross-section, serving substantially to stiffen the rubber body, said I-beam conformation being made up of a thin, rigid, insulatingcarrier core extendingacross the width of the body andirigid metal terminal prongs the widths of which "extend transversely across the ends of said'carrier core, said prongs having slots, the walls of which tightly embrace said core with their outer ends protruding from the face of the plug and a flexible terminal cord extending through the neck of said body and having its inner ends aflixed with respect to the carrier core and in electrical contact with the respective prongs.

15. In a terminal for an electric cord, a plurality of contacts, and a molded, one-piece body portion of resilient insulating material having suitable recesses formed in one end thereof for receiving and supporting said contacts, said body portion also having a centrally disposed passageway extendingithereinto from the opposite end thereof for receiving the cord with which the terminal is used, said passageway being substantially closed adjacent the contact end of said body portion by a slotted barrier which is molded integrally with said body portion and possesses sufliciently inherent flexibility to permit the cord to be drawn entirely through said passageway during the assembling operation.

16. In a terminal for an electric cord, a plurality of contacts, and a one-piece molded body portion of resilient insulating material, which is generally rectangular in cross section, said body portion having suitable recesses formed therein for receiving and supporting said contacts, and also having a centrally disposed, substantially cylindrical passageway formed therein for receiving the cord with which said terminal is used, said recesses extending into said body portion from the larger end thereof, said passageway being open at the smaller end of said body portion and being substantially closed at the opposite end thereof by a'barrier means, said barrier means comprising a section of said body portion which ,is formed with at least one slot therein and which is of suflicient inherent flexibility to permit the cord to be drawn entirely through said passageway during the assembling operation.

17. In a terminal for an electric cord, 2. plurality of prong contacts, and a one-piece molded body portion of resilient insulating material, which is generally rectangular in cross section, said body portion having suitable recesses formed therein for receiving and supporting said contacts, and also having a centrally disposed, substantially cylindrical passage formed therein for receiving the cord with which said terminal is used, said recesses extending into said body portion from the larger end thereof, said passageway being open at the smaller end of said body portion and being substantially closed at the opposite end thereof by a barrier means, said barrier comprising an integral section of said body portion which extends transversely across the contact end of'said passageway, said section having at least one slot formed therein and being of sufficient inherent flexibility to permit the cord to be drawn entirely through said passageway during the assembling operation;

JOSEPH WERTZHEISER, 

